The Nançay Decameter Array

The Nançay Decameter Array (NDA) is observing wavelengths ranging from 3 to 30 meters, corresponding to frequencies ranging from 10 to 100 MHz. It is composed of 144 helical/conical antennas, 9 m high and 5 m wide in diameter, spread across a 7000 m² area, and inclined by about 20° with respect to the zenith.

This phased array (the antenna are fixed and the pointing is achieved electronically) is dedicated to the observation of powerful radio sources, namely the decametric radio emissions radiated by energetic electrons within the magnetized environments of Jupiter and the solar corona.

The NDA observes quasi-daily the Sun and Jupiter since its completion in 1977. It monitors their activity on the long-term, performs observations at very high resolution and ensures a ground-based support to spatial explorations probes (from Voyager to Juno, Parker Solar Probe and Solar Orbiter).